Effects of Lumbosacral and Lumbo-pelvic Fixation and Fusion on Hip Joint Motor Function: A single-center prospective cohort study Using Gait Analysis

Fansheng Zhang¹Shuyuan Bian²Shijia Gaxi³Xiaobin Tian⁴Bo Li^5*Tao Guo^5*

• ¹Medical School of Guizhou University, Guiyang, China
• ²Quzhou City Traditional Chinese Medicine hospital, Quzhou, China
• ³Guizhou University of Traditional Chinese Medicine, Guiyang, China
• ⁴Guizhou Medical University, Guiyang, China
• ⁵Guizhou Provincial People's Hospital, Guiyang, China

Objective: To evaluate the effects of lumbosacral and lumbo-pelvic fixation and fusion on hip motor function using by three-dimensional gait analysis system. Methods: This single-center prospective cohort study enrolled adult patients who underwent lumbosacral or lumbo-pelvic fixation and fusion in the orthopaedics department of Guizhou Provincial People's Hospital from November 2015 to January 2020. Patients were followed postoperatively for over one year. During follow-up, patients’ pain levels, functional impairment, and clinical outcomes were assessed using the Visual Analogue Scale (VAS) score, Oswestry Disability Index (ODI), and Japanese Orthopedic Association (JOA) score. Hip motor function was evaluated through a three-dimensional measurement system that assessed hip, knee, and ankle joints. Data analysis was conducted with SPSS V22.0. This study was designed and reported to adhere to STROBE guidelines for observational research. Results: A total of 30 patients were included in the study, with 15 undergoing lumbosacral peothesis and 15 undergoing lumbo-pelvic fixation. The mean follow-up period was 13.8 months. Kinematic analysis revealed that, compared with healthy controls, patients who underwent lumbosacral fusion showed decreased minimum step length, maximum stride length, maximum angle, and range, while the up-down and up-front displacement increased significantly (p < 0.05). Similar outcomes were observed in patients after lumbo-pelvic fixation and fusion, with an increase in maximum stride length versus healthy controls (p < 0.05). When directly comparing the two groups, those who underwent lumbosacral fusion demonstrated greater maximum stride length, maximum hip flexion angle, and range of hip flexion and extension than those with lumbo-pelvic fixation (p<0.05). Conclusion: Both lumbosacral and lumbo-pelvic fixation and fusion significantly impact hip joint motor function compared to healthy controls. The increased mobility of the femoral head relative to the acetabulum in these patients may elevate the risk of hip osteoarthritis and cartilage wear. Within the scope of parameters measured in this gait analysis, patients receiving lumbosacral fixation demonstrated superiority in specific gait parameters, including maximum stride length and hip flexion-extension range of motion, compared to those undergoing lumbopelvic fixation. This suggests that preserving sacroiliac joint mobility may be beneficial for certain aspects of walking function, when clinically justified.